1. Technical Field
The exemplary embodiment relates to a high-speed industrial roller door having a door leaf which covers the door opening and which is guided in lateral guides, a drive which acts on the door leaf in order to move it from an open position into a closed position and vice versa, wherein in the open position the door leaf is accommodated in a spiral section, arranged in the vicinity of the door lintel, of the lateral guides in such a way that adjacent areas of the door leaf are not in contact with one another, and having a weight compensation device.
2. Related Art
In practical applications, roller doors are known in a wide variety of embodiments. A comparatively simple design of such a roller door is one in which a flexible curtain is wound onto a winding shaft in the vicinity of the door lintel in the course of the opening movement of the roller door. The lintel-side end of the flexible door leaf is, for this purpose, secured to the winding shaft and in the course of the opening movement a continuously growing roll of layers of the curtain is created, wherein these layers can come to rest directly one on the other. Such roller doors have gained widespread acceptance in practice and are often used since they are cost-effective to make available and have a comparatively low weight, which has advantageous effects on energy consumption.
However, a disadvantage of this type of roller door is that the windings of the door leaf which are embodied as a curtain become scratched and soiled after only a comparatively short time owing to the direct mutual contact between them in the roll. This applies equally to roller doors having slatted armor instead of a flexible curtain, as is also known from practical applications.
For specific applications and in particular for high-speed operation with a speed of movement of more than one meter per second, the practice of guiding the door leaf in a contactless manner in the vicinity of the lintel of the door opening has been adopted. Examples of such roller doors can be found, inter alia, in DE 40 15 215 A1, DE 199 15 376 A1 and DE 102 36 648 A1. In these designs, the door leaf, irrespective of whether it is slatted armor or a flexible curtain etc., is guided in lateral guide rails which open in the vicinity of the door lintel above the door opening into a spiral section in which the door leaf is guided in an elongated or approximately round roll.
In contrast to the roller doors explained at the beginning with a curtain which is wound directly onto a winding shaft, when there is contactless guidance the roll does not build up from the inside to the outside but rather from the outside to the inside, that is to say the leading, that is to say lintel-side, end of the door leaf runs increasingly further into a central area of the spiral section in the course of the opening movement of the roller door.
Such roller doors are distinguished by outstanding properties so that they have also gained acceptance particularly in industrial applications. In particular, they permit a reliable and durable door closure to be manufactured with which very high speeds of movement of up to four meters per second are possible.
On the other hand, this method of guiding a door leaf in the roll requires entirely new drive equipment since these designs have made the winding shaft itself vulnerable. Although the drive motor in these roller doors is still arranged in the region of the door lintel for reasons of space, the application of the drive force to the door leaf occurs at the floor end. In the embodiments which are customary at present, the drive motor usually acts via a toothed belt on drive rollers in the form of toothed belt pulleys which are arranged on each side of the door, also in the vicinity of the door lintel, and each in turn act via a toothed belt on a strap or the like which is rigidly coupled on both sides to the floor end of the door leaf. The two lateral toothed belts are fixedly connected to the straps or the like in this context so that the rotational movement of the drive motor ultimately causes the door leaf to be raised or lowered.
In particular in the case of door leaves which are embodied as slatted armor, it has also become acceptable practice in this context if a weight compensation device is provided which serves to balance the weight of the door leaf of a lifting door. This weight compensation device typically has spring elements which are under maximum prestress when the door is closed, and therefore support the opening movement of the door leaf. However, this not only reduces the drive torques necessary for the activation of such a lifting door but also, given correct adjustment of the arrangement, prevents the door leaf from dropping suddenly in the event of a fault.
In practical applications, high-speed industrial doors with weight compensation devices of a design such as is explained, for example, in WO 91/18178 have become widespread. Such a weight compensation device typically, has as the spring element, a helical spring and a tensile element which is attached thereto and is generally in the form of a belt. The lower end of the tensile element is in this context fixedly connected to the floor while its upper end is coupled by the tensile element to a winding shaft which is arranged at the lintel side of the lifting door. In this context, in the course of the closing process of the lifting door the tensile element is wound onto this winding shaft with layers which rest directly one on the other so that the spring element is increasingly stressed. On the other hand, the opening movement of the door leaf is associated with an unwinding process of the tensile element from the winding shaft so that in this context the stress of the spring element is released. The winding shaft is coupled to the drive of the lifting door here.
This method of driving a roller door has also been proven in practical application for many years. However, the elements of the drive mechanism are subject to a considerable risk of damage if the door leaf coincides with another object.
In this context it is necessary to take into account the fact that the floor-side end of a door leaf is particularly at risk in terms of collisions. Such collisions may occur, for example, if a forklift truck driver incorrectly estimates the speed of movement of the door leaf and sets his vehicle in motion too early in the course of the opening movement of the door leaf. Further sources of danger frequently occur if large-side goods are transported which restrict the field of vision. Such collisions then usually result in a deformed or broken closure element of the door leaf, and at the same time the lateral straps or the like of the drive mechanism which are present in the lateral guides may also be damaged.
In order to counter this problem, the applicant has developed an active crash system which, in the event of a collision, permits the lower section of the door leaf to be deflected out of the plane of the door leaf as soon as a predetermined value of a lateral force is exceeded. This development has also given rise to the roller door with collision protection which is described in German patent application DE 103 42 302 A1. With this system it is possible very largely to avoid the damage to the door leaf which adversely affects the functioning of the roller door. Furthermore, the risk of damage to the elements of the drive mechanism can also be considerably reduced in this way since as soon as the door leaf is deflected in the central area of the door opening the straps etc. which are present in the lateral frames are freed of the loading which usually occurs in said central area of the door opening.
Despite the considerable advantages in practical application, this specific roller door with the active crash system is subject to the problem that when the door leaf is deflected there is no longer a closure element present which brings about a transverse connection between the two lateral guide devices. The points of an engagement for the application of the drive force to the door leaf are therefore no longer supported on one another in the event of a collision, which causes tilting moments to occur in the lateral guides. Even if these tilting moments can be limited by correspondingly precise guide elements, this nevertheless results in increased wear and constitutes a considerable additional cost factor. Furthermore, in unfavorable cases it is still impossible to prevent the coupling points for the drive force from also being damaged in the event of a collision, for example if a collision occurs directly adjacent to the lateral frames.